1. Field of the Invention
The present invention relates generally to a wireless communication network, and in particular, to a method for supporting packet destination in a wireless communication system supporting a packet data service.
2. Description of the Related Art
With the development of the communication technology, various techniques for combining an IP (Internet protocol)-based packet network with a wireless communication network have been proposed. A most typical one of those techniques is CDMA 2000 (Code Division Multiple Access 2000) system. In the CDMA 2000 system, voice or data is transmitted to an IP network over an IP packet, and the IP network transmits the IP packet to a mobile station (MS, or mobile node or mobile host) having a unique IP address. Similarly, the mobile station with the unique IP address transmits the IP packet to a correspondent node (CN). The term “packet call service” as used herein refers to all kinds of a packet-based voice or data call transmitted from a transmitter to a receiver over the whole or partial route there between.
In a wireless communication system supporting such packet communication, in order to be provided with a packet call service, a mobile station must have a unique address so that the mobile station can be identified in a packet network. In an IP network, the unique address becomes an IP address. Preferably, mobile stations must each have their own unique IP address. However, since the number of available IP addresses is limited, a technique for temporarily allocating an IP address only when a packet call is connected is chiefly used.
In a CDMA 2000 1x wireless communication system, nodes capable of allocating an IP address to a mobile station include a packet data service node (PDSN) and a home agent (HA). The packet data service node allocates an IP address to a mobile station requiring a Simple IP allocation service, while the home agent allocates an IP address to a mobile station requiring a Mobile IP allocation service. An IP address allocated by the packet data service node is deleted when the service is ended, whereas an IP address allocated by the home agent remains unchanged unless the mobile station moves to coverage of another home agent (i.e., to another domain).
In this case, an IP address allocated to a mobile station is changed each time the mobile station accesses a packet network and initiates a service, or each time a handoff occurs as the mobile station changes an access point (or position) of the packet network. Therefore, a common Internet user cannot recognize a current IP address of a mobile station with which he or she desires to communicate, so it is not possible to set up a packet data destination call to the mobile station. That is, when dynamically allocating an IP address to a mobile station, a correspondent node cannot recognize an IP address of the mobile station, so that the correspondent node cannot first initiate communication. This means that the mobile station can support packet call origination but cannot support packet call destination. Therefore, the mobile station cannot serve as an Internet server.